18.3 PROM Programming
Table 18-4 indicates how to select the program, verify, and other modes in PROM mode.
Table 18-4 Mode Selection in PROM Mode
Pins
Mode
CE
OE
PGM
V
PP
V
CC
EO
7
to EO
0
EA
16
to EA
0
Program
L
H
L
V
PP
V
CC
Data input
Address input
Verify
L
L
H
V
PP
V
CC
Data output
Address input
Program inhibited
L
L
L
V
PP
V
CC
High impedance
Address input
L
H
H
H
L
L
H
H
H
Legend
L:
Low voltage level
H:
High voltage level
V
PP
: V
PP
voltage level
V
CC
: V
CC
voltage level
Read/write specifications are the same as for the standard HN27C101 EPROM, except that page
programming is not supported. Do not select page programming mode. A PROM programmer that
supports only page-programming mode cannot be used. When selecting a PROM programmer,
check that it supports a byte-at-a-time high-speed programming mode. Be sure to set the address
range to H'00000 to H'1FFFF.
18.3.1 Programming and Verification
An efficient, high-speed programming procedure can be used to program and verify PROM data.
This procedure programs the chip quickly without subjecting it to voltage stress and without
sacrificing data reliability. Unused address areas contain H'FF data. Figure 18-4 shows the basic
high-speed programming flowchart. Tables 18-5 and 18-6 list the electrical characteristics of the
chip during programming. Figure 18-5 shows a timing chart.
562
www.DataSheet4U.com